Arachis hypogea

Abstract

DISTRIBUTION: Peanuts, an important cash crop, is an annual legume. Its cake is used as feed or for makingt other food products and haulms provide quality fodder. Peanuts are mainly grown in the Free State, Northwest and Northern Cape. Botanical description: Underground nuts, pulled up and dried in heaps in sun and covered by grass or plastic cover is biggest problem.

TOXIC PRINCIPLE: • Aflatoxins are very poisonous mycotoxins produced by the Aspergillus flavus fungus that was discovered in 1961 in stored peanuts. • In South Africa peanut oil cake is the usual culprit. • Aflatoxins are derivatives of difuranocoumarins. • AFB1 and B2 (blue fluorescense under ultraviolet light). • AFG1and G2 (fluoresce a greenish-yellow). • Acute aflatoxicosis occurred as sporadic farmyard disasters. • Not so common now. • Chronic aflatoxicosis is more common.

SYNDROMES: Aflatoxicosis Hepatotoxic syndrome without photosensitization

SYSTEMS AFFECTED: Liver.

CLINICAL SIGNS: • Primary organ affected is the liver - degeneration and necrosis of hepatocytes. • Interferes with protein synthesis.• Blood clotting interfered with. • Immunosuppression: reduced resistance to secondary infections. • Severe decrease in production, growth, feed conversion, etc. • Aflatoxin B1: most potent hepatocarcinogen known at present. Acute: • Sudden death • Anorexia, depression, haemorrhages, convulsions, death. Subacute: • Icterus, haemorrhagic enteritis, haematomas. Chronic: • Decreased feed efficiency, productivity and weight gain, icterus, anaemia, oedema, ascites.

NECROPSY: • Very similar to pyrrolizidine alkaloid poisoning (Seneciosis). • Apart from hepatic fatty degeneration, necrosis and fibrosis, extensive bile duct hyperplasia is seen. • In chronic cases intralobular fibrosis, especially in the centrilobular region resulting in veno-occlusive disease. • Nodular hyperplasia - “hob-nailed” liver may be seen.

TREATMENT: • Withdraw contaminated feed. • Low fat, adequate protein diet. • Liver supportive therapy. • Activated charcoal.• Antimicrobial therapy e.g. penicillins (immunosuppression).